It is known to combine articles into groups to form packaging units. The articles are generally bottles, such as plastic bottles. However, similar processing is carried out with cans.
The packaging unit is typically wrapped in plastic film that is then shrunk so that the articles form a stable packaging unit. The articles are secured against each other by means of the shrink-wrap film.
It is known to form pairs of flaps that are then folded around horizontal or vertical axes. After being folded, the flaps are then exposed to heat for welding.
A problem that sometimes arises is that the flaps can at least partially come loose. Thus, the film wrapper, which should be closed on all sides, develops an unintentional opening in the area of the flaps. In the extreme case, articles can fall through this hole. This is particularly true when the articles are very heavy. Heavy drink cans and bottles are thus particularly vulnerable to being lost in this way.
It is known to secure individual flaps reciprocally in the overlap area by using an existing or introduced adhesive or by a weld. A shrink process then takes place in a shrink tunnel. This improves the stability of the resulting packaging unit. However, even with this process, individual flaps may be unintentionally open as a result of the deformation associated with the shrinking.